/*
 * Copyright (C) 2009 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.util.concurrent;

import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import javax.annotation.Nullable;

/**
 * A {@link ListenableFuture} whose result can be set by a {@link #set(Object)},
 * {@link #setException(Throwable)} or {@link #setFuture(ListenableFuture)} call. It can also, like
 * any other {@code Future}, be {@linkplain #cancel cancelled}.
 *
 * <p>
 * {@code SettableFuture} is the recommended {@code ListenableFuture} implementation when your task
 * cannot be implemented with {@link ListeningExecutorService}, the various {@link Futures} utility
 * methods, or {@link ListenableFutureTask}. Those APIs have less opportunity for developer error.
 * If your needs are more complex than {@code SettableFuture} supports, use {@link AbstractFuture},
 * which offers an extensible version of the API.
 *
 * @author Sven Mawson
 * @since 9.0 (in 1.0 as {@code ValueFuture})
 */
@GwtCompatible
public final class SettableFuture<V> extends AbstractFuture.TrustedFuture<V> {
    /**
     * Creates a new {@code SettableFuture} that can be completed or cancelled by a later method
     * call.
     */
    public static <V> SettableFuture<V> create() {
        return new SettableFuture<V>();
    }

    @CanIgnoreReturnValue
    @Override
    public boolean set(@Nullable V value) {
        return super.set(value);
    }

    @CanIgnoreReturnValue
    @Override
    public boolean setException(Throwable throwable) {
        return super.setException(throwable);
    }

    @Beta
    @CanIgnoreReturnValue
    @Override
    public boolean setFuture(ListenableFuture<? extends V> future) {
        return super.setFuture(future);
    }

    private SettableFuture() {}
}
